Rail-heating device



Aug, 21, 19281 1,681,231

W. H. GREENFIELD RAIL HEATING' DEVICE Filed may 1 1927 r it 7 INVENTOR: W fm Wk Patented Aug. 21, 1928.

UNITED! STATES PATENT OFFICE.

WILLIAM H. ennnnrmnn, or PHILADELPHIA, PENNSYLVANIA.

BAIL-HEATING nnvrcn Application fled May 12, 1397. :Serialli'o. 190,988.

My invention relates to rail heating devices and more particularly to electric heaters designed to prevent the accumulation of ice and snow around rail switches and derail points without interferencewith their operation. Primaril the invention consists 0 heat radiatingumts positioned at switch or derail 'pointsor at intervals along a"railway track, the units being electrically op erated from local or distant stations.

To fully explain the object of my invention I shall refer briefly to the operation of well-known types of rail heaters. Heretofore, it has been common in this art to heat rails by resistance conductors extend- 7 as not been able to withstand the vibration or the severe weatherconditionsto which railwa tracks are subjected. 1

"1 0 obviate the foregoing difiiculties, my invention provides a means of heating rails I! by direct radiation from-a high resistance heating element which is adapted to raise the temperature of the rail to which it is attached to a sufficiently high degree to prevent the formation of (ice or snow in the neighborhood of the rail. My invention provides a means of reducmg losses in heat transmission to a. minimum.

Supplementing the advantages already described are those derived from the use of a m heating device which though durable and waterproof is nevertheless simple 1n structure and inexpensive to manufacture.

Other features and advantages of my in-,

vention will be apparent from the detailed description which follows, the description having reference tothe accompanying drawings which represent a ty cal embodiment of the invention, and in w ich:

Fig. I is a perspective view of the heating to element and the casing in which it is retained. i

Fig. II is a perspective view of a portion of a rail, illustrating one form of my invention in place.

Fig. III is a cross sectional view of a rail with the heater attached taken as indicated by the arrows III-III in Fig. IV.

Fig. IV is a cross sectional view of the same taken as indicated by the arrows IV IV, in Fig. III, and

.F V is an enlarged sectional viewof oneend of the casing illustrating the method by "which the heating element is secured to the casing and insulated therefrom.

In the drawings there is shown a portion of an ordinary track switch comprising .a main rail R with a heating unit of convenient size attached to the hollow of the rail and enclosed in a protective casing comprehensively designated by the numeral; 6. To secure the casing '6 to the rail R the end pieces 8 are provided with ears 9 which may be bolted or otherwise firmly held-against the central web of "the rail. Apertures .13 in the end pieces 8 admit passage of the electrical conductor'lfi through the casing to a the heatingJele-ment 5. In electric connection with the conductor 12 the heating element 5 occupies the trough of the fillet juncture betweenthecentral web and base flange of, the rail R, but contacts only withthe sockets 14 in which it is supported. The casi 6 is preferably lined with asbestos 7 or ot er heat insulating material in order to retain the heat radiating from the element .5 within the enclosure bounded by the casing and the hollow of the rail. The

lining 7 ialsoafit'ords a reflecting surface to direct the radiation from the heating element 5 towards the rail R.

Referring particularly to Fig. V, I have illustrated one form of bushing for supporting the heating element 5 within the casing 6. It comprises a porcelain insulator 11, fitting in the rounded flange 10 of the easing 6 through which the conductor 12 is free to pass, together with a terminal socket 14 to which the bared wire issealed. The

socket 1 5} is adapted to receive the end of the heating element 5 in its hollowed recessin a helical spring 15 is provided to enable movement of the insulator 13 so that the heating element 5 may be removed with ease. The interior of the insulator 11 is shown filled with plaster 16 for securing the con-- ductor'12 a firm conneotien with its termi- 1121.1 14;. Between the insulator l0 and the terminal socket 14 a washer 17 is interposed.

The heating element 5 may consist of an elongated rigid non-metallic resistor bar of convenient size and olfering high resistance to the passage of current. F or this purpose, I preferably employ what is commercially known as a glow bar, being a carborundum element especially suitable as a resistor bar. Likewise I may employ a heating element known as nichrome or any of the materials commonly used as resistance conductors. By virtue of its close proximity to the web and bottom flange of the rail R, the resistor bar 5 is capable of transmitting intense heat to the exposed surfaces of the rail. As the enclosure bounded by the hollow of the rail R and the heat insulated casing (3 is entirely devoid of heat conducting elements with the exception of the rail itself the air in the enclosure serves as the sole medium of heat transmission between the element 5 and the rail. Thus, heat losses by conduction are reduced to a minimum. l urthermore, the base flange of the rail is directly exposed to heat radiation, this being the portion of the rail which it is most desirable to heat to eli'eet a thorough melting of ice or snow around switch points.

In the ar'angemcnt shown, the heating unit is waterproof and well protected from injury. By slight modification in the shape of the casing the heater may be adapted for use on rails at points where fish plates or through bolts are located Without departing from the scope of the present invention.

It will be apparent that the device may also be adapted for use on third rails or current carrying rails, the heating circuit being insulated and independent of the rail to which it is attached. By reason ofthe portable character of the units they may be installed either for permanent or temporary use. When permanently installed the resistance bars 5 may be easily replaced or removed-by virtue of the peculiar construction of the spring actuated sockets in which they are held.

Having thus described my invention, I claim: A

1. A rail heating device comprising a bare electric heating element, and means to support said element in spaced relation from the rail with air serving as the sole medium of heat transmission therebetween.

2. A. rail heating device comprising a bare electric heating element in the form of an elongated resistor bar, and means engaging the bar at opposite ends to support it in longitudinally spaced relation from the rail with air serving as the sole medium of heat transmission therebetween.

El. A rail heating device comprising a bare electric heating element in the form of a rigid elongated resistor bar, and yielding means releasably engaging the bar at opposite ends to support it in longitudinally spaced relation from the rail with air serving as the sole medium of heat transmission between the resistance bar and the rail aforesaid.

4. A rail heating device comprising a bare electric heating element, means to support said element in spaced relation from the hollow of the rail with air serving as the sole insulation therebetween, and a protective casing affording a reflecting surface to direct radiation from the heating element toward the rail.

41A rail heating device comprising an electrical resistor bar, means to support the bar longitudinally within the trough of the fillet juncture between the web and base flange of they rail with air serving as the sole insulation therebetwcen, and a protective casing affording a reflecting surface to direct radiation from the bar inwardly toward the rail as well as downwardly toward the base flange.

6. A rail heating device comprising a bare electric heating element in the form of a rigid elongated resistor bar, and spring rged sockets releasably engaging the bar at opposite ends to support it in longitudinally spaced relation from the hollow of the rail with air serving as the sole insulation betweenthe bar and the rail aforesaid.

7. A. rail heating device comprising a casing secured to the rail and extending therealong, and an electrical heating element in the form of a rigid resistor bar centrally located in the space between said casing and rail whereby the web and base flange of the rail are exposed to direct radiation from the heating element.

8. A rail heating device comprising a casing having end pieces secured to the rail, said casing forming with the hollow of the rail an enclosure of substantially triangular cross section, and an electrical heating ele ment in the form of a rigid elongated rcsistor bar centrally disposed within the enclosure and supported at its ends by the said end pieces.

9. A rail heating device comprising a casing extending along the rail and having end pieces secured thereto, said casing forming with the web and base flange of the rail a heat insulated enclosure, an electrical heating element in the form of a resistor bar centrally located in the enclosure and supported at its ends by the end pieces of the casing, and means to electrically insulate the bar from the casing.

10. A rail heating device comprising a protective casing secured to the rail and extending therealong, and a rigid non-metallic electrical resistor bar intermediate the easing and rail and adapted to heat the hollow of the rail solely by radiation.

In testimony whereof, I have hereunto signed my name at Philadelphia, Pennsylvania, this twenty-eighth day of April, 1927.

lVILLIAM H. GREENFIELD. 

